1. Field of the Invention
The present invention relates to a photoelectric conversion device having a circuit including a transistor.
2. Description of the Related Art
A number of photoelectric conversion devices used for detecting electromagnetic waves are generally known. For example, photoelectric conversion devices having sensitivity ranging from ultraviolet rays to infrared rays are collectively referred to as optical sensors. An optical sensor having sensitivity to light in a visible light region with a wavelength of 400 nm to 700 nm is particularly referred to as a visible light sensor. A large number of visible light sensors are used for devices that require illuminance adjustment, on/off control, or the like depending on human living environment.
Known examples of visible light sensors are a photodiode that is a photoelectric conversion element utilizing photoelectric conversion properties of single crystal silicon or amorphous silicon, and a photo IC provided with a phototransistor or an amplifier circuit that amplifies an output of a photodiode.
For example, Patent Document 1 discloses an example of a photo IC in which a photodiode using amorphous silicon and an amplifier circuit using polycrystalline silicon are formed over one substrate.